package com.bcxj;

import org.apache.flink.api.common.typeinfo.Types;

import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.AggregateOperator;
import org.apache.flink.api.java.operators.DataSource;
import org.apache.flink.api.java.operators.FlatMapOperator;
import org.apache.flink.api.java.operators.UnsortedGrouping;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;

/**
 * ClassName: BatchWordCount
 * Package: com.bcxj
 * Description:
 *
 * @Author BCXJ
 * @Create 2024/6/1 09:58
 * @Version 1.0
 * @Since 1.0
 */
public class BatchWordCount {
    public static void main(String[] args) throws Exception {
        // 1 创建执行环境
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

        // 2 从文件读取数据，执行读取(存储的元素就是每一个文本)
        DataSource<String> lineDS = env.readTextFile("input/words.txt");

        // 3 转换数据的格式 ， Collector<Tuple2<String, Long>> out 就是采集器
        FlatMapOperator<String, Tuple2<String, Long>> wordAndOne =
                lineDS.flatMap((String line, Collector<Tuple2<String, Long>> out) -> {
            String[] words = line.split(" ");

            for (String word : words) {
                out.collect(Tuple2.of(word, 1L));
            }
        }).returns(Types.TUPLE(Types.STRING, Types.LONG));


        // 4 按照指定的规则进行分组
        UnsortedGrouping<Tuple2<String, Long>> wordAndOneUG = wordAndOne.groupBy(0);

        // 5 分组聚合统计
        AggregateOperator<Tuple2<String, Long>> sum = wordAndOneUG.sum(1);

        // 6 打印结果
        sum.print();
    }
}
